Process of decolorizing petroleum distillates



, therew1th1/40 to 1/5 lb. of sulphuric aoi Patented Oct. 12, 1926.

UNITED STATES PATENT OFFICE.

RALPH C. POLLOCK, OF LONG.BEACH, CALIFORNIA, ASSIGNOR TO UNION OIL COM-PANY OF CALIFORNIA, OF LOS ANGELES,

IROCESS OF DECOLOBIZING PETROLEUM DISTILLATES.

FOBNIA.

No Drawing. Application filed April 4,

My invention relates to the treatment of petroleum distillates for thepurpose of decolorizing the same.

The principal object of my invention is to treat a distillate ofpetroleum by a process which decolorizes the same without subjecting thedistillate to the usual acid and alkali treatments. v

The specific distillate which I treat by my process is commercialgasoline such as for instance of the grade which has an initial boilingpoint of 130 F. and an end point of 430 F., but I do not limit myself tothe treatment of this grade of gasoline alone, inasmuch as my inventionmay be racticed within the limits hereinafter described and claimed.

The character of gasoline, as to its chemical components and thephysical characteristics thereof, and particularly as to its color,varies largely according to the different 10 calities from which thecrude oil originates and from which the gasoline is distilled and varieswith the method of distillation used.

Thus the characteristics of gasoline might be said to vary with eachindividual crude oil well, and in general the characteristics ofgasoline obtained from California .crude oil are greatly different fromthe gasoline obtained from Pennsylvania crude oil, although in somespecific points they may be alike.

Also, the so-called straight run gasoline difl'ers largely from thegasoline obtained by the so-called cracking process, wherein aconversion of heavy oil into gasoline takes place.

It is in all cases, generally customary to treat the gasoline first withsulphuric acid of different strengths and quantities for the removal ofsuch constituents of the gasoline as are'harmful to the commercial usethere-- of, and included in these constituents are such compounds ascause an objectionable color to the gasoline. After treating thegasoline with acid, it is usually washed with water and then treatedwith an alkali and washed again.

The various acid, alkali and water washes arewcry expensive and. I havediscovered that by taking a gasoline and agitatin 50 to 98 percentstrength, for each barrel of gasoline, then adding a ground clay in1923. Serial No. 629,874.

are such as' to permanently decelorize the gasoline.

With .most gasoline if an excess of acid is used, the gasoline retains apinkish color, and with certain gasolines and under certain conditionsif an excess of a. neutral or alkaline earth is used, the gasoline isdecolorized,

but, after standing for some time, the color will return.

The clay used maybe practically .any of the decolorizing clays now inuse, without having gone through any process whereby the clays areespecially prepared for decolorizing purposes by acid treatment.

The agitation of" gasoline, with acid and v clay may be by mechanicalmeans or by air etc. and I find that the action of the acid and clay onthe gasoline, in the above men- ,tioned proportion, is such that thereis no acid sludge formed, or if there is such it is completely adsorbedby the clay and invisible to the eye. Thus, a great economy resultsinthe application of my process togasoline, wherebythe cost of preparingthe same for market is a minimum. For instance, inv addition toeliminating the heavy acid and alkali washes, I am enabled to use a clay.now costing in the neighbourhood of $25.00 per ton whereas a treatedclay for the same purpose costs $65.00 per ton.

The proportions of acid and clay to each barrel (42 gallons) of gasolinemay be varied within the limits mentioned in order to efl1'ect thedesired results the quantity of 'acid requiredvarying withthe-weight ofthe product treated, whether gasoline, engine distillate, or lubricatingoil, and also varying with the relative change in color desired. Thequantity of clay required varies with the amount of acid used and shouldalways be suflicient to prevent the final product from having an acidreaction and ifdesired the selected proportion of acid maybe used toacidity the selected proportion of clay before the same are mixed withthe gasoline.

CALIFORNIA, A CORPORATION OF CALI- Various methods, for variouspurposes, are known for treating petroleum distillates with acid andclay in turn, or .with an acid treated clay for decolorizing, but in thefirst case a heavy sludge has to be removed after acid treatment and inthe. latter case the chemical and physical actions are quite differentfrom my invention.

Apparently I have invented a new method of decolorizing rectifiedgasoline and other petroleum distillates, in which an earth or clay isacid-treated in the presence of gasoline or distillate, and after beingthus activated the earthy material brings about a permanentdecolorization of the stock in contrast to the temporary result obtainedby the use of raw earth alone. In this new method, by using a smallamount of acid and raw earth, the activation of the earth and thedecolorization of the gasoline or distillate may properly be consideredas parts of a single operation.

It is evident that decolorization only is actually brought about asindicated above, because the amount of acid used, 1/40 to 1/5 pound tothe barrel of gasoline, is too small to have any appreciable refiningaction in itself and no discernible sludge is formed from thedistillate. This is particularly evident in those cases in which acid ofonly 50 per cent concentration is used. Also it has been shown that rawearth alone will not yield a permanently decolorized product. On theother hand it has been found that if the small amounts of acid and claymentioned are merely mixed together before adding to the gasoline apermanent decolorization is obtained. But to mix the acid and earth in aseparate operation is inconvenient and costly and would require specialapparatus, therefore in my new method the acid and earth areconveniently brought together in the regular agitating apparatus in thepresence of the d1stillate which is to be treated.

The clays used may be taken from various sources and I have successfullypracticed my invention with many California clays from differentlocalities having different compositions, but the decolorizing efiected'is uniform provided the proportions of acid and clay are maintained asdescribed. Considering a barrel of gas oline of 42 gallons as weighingabout 270 pounds, these proportions ran e from one ten-thousandths toone-thousan th part by weight for the acid and from one three-thousandthto one one-hundredth part by weight for the clay or earth, these'generalproportions being equally applicable to the heavier petroleumdistillates, such as engine distillate and lubricatin oil.

It is of course un erstood that after the gasoline is agitated with theacid and clay,-

or acid treated clay, having the proportions of acid and clay described,that any residue is removed from the treated. gasoline by settling, orby running through a filter, or in any well known manner.

In referring herein to clay and earth, the terms are interchangeablewith respect to the operation herein descirbed, for I have not only usedraw clays, but also ordinary earth, or soil successfully. In fact,almost any earthy, or earth-like, material will proportionately servefor activation with acid to decolorize petroleum distillates with mymethod. The weight of a barrel of gasoline of 42 gallons is taken at 270pounds and thus it is seen that the percentages of acid and clays usedare not more than 1% each of the weight of gasoline treated.

I claim 1. The process of removing color from a mixture of liquidhydrocarbons of petrole: um origin which consists in agitating thecolored hydrocarbons with non-fuming sulphuric acid and an earth and inlater separating the residue from the treated hydrocarbons, the amountof acid used depending upon the specific gravity and upon thehydrocarbons and the relative amount of change of color desired, andranging from a ten-thousandth part by weight to a thousandth part byweight, and the amount of eartih depening upon the weight of acid use 2.The processof removing color from a mixture of liquid hydrocarbons ofpetroleum origin which consists in agitating the colored hydrocarbonswith non-fuming sulphuric acid and earth and in later separating theresidue from the treated hydrocarbons, the amount of earth requireddepending upon the specific gravity and upon the hydrocarbons and therelative amount of change of color desired, and ranging from athree-thousandth part by weight to one hundredth part by weight, and theweight of the acid used being insufficient to cause an acid reaction inthe final product..

3. The process of removing color from a mixture of liquid hydrocarbonsof petroleum origin which consists in agitating the colored hydrocarbonswith from a ten-thousandth to a thousandth part by weight of sulphuricacid and with from a three-thousandth to a one-hundredth part by weightof earth, and in separating the residue from the treated hydrocarbonswithout first removing a portion of the acid as in the usual refinerypractice method.

4. The process of removing color from a mixture of liqpid hydrocarbonsof petroleum origin which consists in agitating the colored hydrocarbonswith from a tenthousandth to a thousandth part by weight of non-fumingsulphuric acid and then, in thepresence of all of the acid, adding froma three-thousandth to .a hundredth part by weight of clay, furtheragitating the entire from 1/10 to 2 pounds of clay per bari'el ofmixture, and. finally separatin outthe resithe gasoline, and finallyseparating the due from the treated hydrocar ons. residue and theclarified gasoline. 1 5 The ppocess of clarifying gasoline which Signedat Wilmington, in the conty of 5 consists in agitating the gasoline inthe res- Los Angeles, and State of California, this ence of from l/40 to1/5 of apound o sul- 30th day of March A. D. 1923. pliuric acid perbarrel of the gasoline, and RALPH C. OLLOCK.

